BREAKING CHANGES: Rename internals

BREAKING CHANGES:
Class.toString now returns the init method body
Renaming internal properties and certain magic properties.
Change behavior of the bind mutator to make context a property instead of a argument.
```javascript
// calling parent method
this.parent => this.$$parent
this.invoke => this.$$apply
adding this.$$call
// internal variables
Class.superclass => Class.$$superclass
Class.subclass => Class.$$subclass
Class.implement => Class.$$implement
Class.mutators => Class.$$mutator
Class.applicate => Class.$$apply
Class.__isclass_ => Class.$$isclass
// bind mutator
function(context) {} => function() { this.$$context; }
// shortcuts
removed this.self, use Class.prototype.constructor/this.constructor instead
```